LocalDateTime

src/chapter5/Example20.java

@@ -1,4 +1,12 @@
 package chapter5;
 
+import java.time.Instant;
+
 public class Example20 {
+    public static void main(String[] args) {
+        Instant now = Instant.now();
+        System.out.println(now);
+        Instant instant = Instant.ofEpochMilli(1000 * 60 * 60 * 24);
+        System.out.println(instant);
+    }
 }

src/chapter5/Example21.java

@@ -14,11 +14,20 @@ public class Example21 {
         System.out.println("今年中的第几天：" + now.getDayOfYear());
         System.out.println("周几：" + now.getDayOfWeek());
 
-        System.out.println("====判断相关的方法====");
+        System.out.println("\n====判断相关的方法====");
 
         System.out.println("of是否在now之前？" + of.isBefore(now));
         System.out.println("of是否在now之后？" + of.isAfter(now));
         System.out.println("of和now是否相等？" + of.isEqual(now));
         System.out.println("of是否闰年？" + of.isLeapYear());
+
+        System.out.println("\n====解析和加减操作====");
+
+        String dateStr = "2020-02-12";
+        LocalDate date = LocalDate.parse(dateStr);
+        System.out.println("把字符串转换为日期对象：" + date);
+        System.out.println("年份加1:" + date.plusYears(1));
+        System.out.println("天数减5:" + date.minusDays(5));
+        System.out.println("指定年份为2024：" + date.withYear(2024));
     }
 }

src/chapter5/Example22.java

@@ -0,0 +1,30 @@
+package chapter5;
+
+import java.time.LocalTime;
+import java.time.format.DateTimeFormatter;
+
+public class Example22 {
+    public static void main(String[] args) {
+        // 1. 获取当前时间
+        LocalTime now = LocalTime.now();
+        // 2. 表示过去时间
+        LocalTime of = LocalTime.of(9, 23, 23);
+        // 3. 三个getter
+        System.out.println("时：" + now.getHour());
+        System.out.println("分：" + now.getMinute());
+        System.out.println("秒：" + now.getSecond());
+
+        // 4. 格式转换，借助 DateTimeFormatter
+        System.out.println("\nnow默认格式：" + now);
+        System.out.println("不显示微秒：" + now.withNano(0));
+        System.out.println("转换格式：" + now.format(DateTimeFormatter.ofPattern("HH:mm:ss")));
+        System.out.println("转换格式：" + now.format(DateTimeFormatter.ofPattern("HH点mm分ss秒")));
+
+        // 5. 判断
+        System.out.println("\nof在now之前吗？" + of.isBefore(now));
+
+        // 6. 解析字符串
+        LocalTime time = LocalTime.parse("12:15:30");
+        System.out.println("将字符串转换成时间对象：" + time);
+    }
+}

src/chapter5/Example23.java

@@ -0,0 +1,4 @@
+package chapter5;
+
+public class Example23 {
+}